Pipe upsetting



April 1960 A. F.- KRITSCHER 2,932,889

PIPE UPSET'I'ING Filed July 20. 1955 2 Sheets-Sheet 1 BY! AD L Akzzm his Attorney.

April 19, 1960 A. F. KRITSCHER 2,932,889

PIPE UPSETTING Filed July 20. 1955 2 Sheets-Sheet 2 Bis-Z 4- INVENTOR. ANDREW E KR/TSCHER,

his Attorney.

2,932,889 I PIPE UPSE'I'IING Application July 20, 1955, Serial No. 523,238 "4 Claims. c1. 29-s4z This invention relates to an improved method and apparatus for externally upsetting pipe ends. I

In the metal pipe art, upsetting refers to a forging operation in which the walls at the end of a pipe are made thicker for a length of several inches. Upsets can be either internal, external, or a combination of both. To form an external upset, metal must be forced into a closed cavity. Consequently external upsets are more diflicult to form than internal upsets, where metal is forced into an open cavity. According to usual practice, a single external upsetting operation can increase the wall thickness to a maximum of about 1.4 times the original thickness, while a single internal upsetting operation can increase the thickness to about twice the original. To take advantage of the greater ease with which internal upsets are formed, it has been proposed to form external upsets by expanding internal upsets. However, previous practices of this type necessitate a large number of operations and different tools for each, and thus afford a negligible advantage over forming an external upset directly.

An object of the present invention is to provide an improved method and apparatus for externally upsetting a pipe end in which the end is first upset internally and then expanded with a single in-and-out movement of the same tool.

A further object is to provide an improved method of externally upsetting pipe ends in which the wall thickness can be increased by approximately twice the original thickness in a single operation.

A further object is to provide an improved upsetting apparatus which embodies a mandrel, a'set of dies, and a yoke capable of forming an internal upset on an instroke and of expanding this upset to an external upset on an outstroke.

In accomplishing these and other objects of the invention, I have provided improved details of structure, a preferred form of which is shown in the accompanying drawings, in which:

Figure l is a longitudinal sectional view of an upsetting apparatus constructed in accordance with my invention in its starting position;

Figure 2 is a view similar to Figure 1, but in the position immediately preceding the internal upsetting operation;

Figure 3 is another similar view, but in the position immediately following the internal upsetting operation;

Figure 4 is another similar view, but in the position immediately preceding the expanding operation; and

Figure 5 is still another similar view, but in the position at the conclusion of the expanding operation.

Figure 1 shows a set of conventional internal upsetting dies and 12 and the end portion of a pipe P mounted therein. Both dies are movable toward or away from the pipe, and when closed as shown, have a slight clearance with the outside of the pipe. The pipe is gripped against lengthwise movement rearwardly of the dies by conventional means not shown. It would also be pos- Pa., assignor to United ice;

. 2 sible to gripwith the dies. The end portion of the pipe is previouslyheated to an appropriate forging temperature. A stationary frame 13 is mounted in spaced relation to the dies and carries a double acting power driven reciprocable ram 14 which is coaxial with the pipe.

A mandrel 15, constructed in accordance with my invention, is fixed to the end of the ram 14. The mandrel includes a cylindrical section 16 adjacent the ram, a section 17 of smaller diameter and preferably tapered slightly extending therefrom, and a head 18 at the extremity of the latter section. The maximum. diameter of the head is slightly smaller than the inside diameter of the pipe to insure against forcing metal into a closed cavity. The head has a sloping planishing surface 19 which leads to the section 17 of smaller diameter. This surface slopes at about 7 /5 to 15 with respect to the horizontal. The diameter of the section 17 is sufiiciently smaller than that of the pipe to leave an annular recess of greater volume than the internal upset to be formed. The length of this section approximately equals that of the upset.

Also in accordance with my invention, the frame 13 carries a pair of guide pins 20 on which an annular stripper yoke 21 is mounted for free sliding movement coaxial with the mandrel 15. This yoke includes a base portion 22 adapted to abut the frame 13 and ram 14, and a sleeve portion 23 adapted to abut the pipe end. The mandrel 15 extends through both portions of the yoke 21 and is freely movable with respect thereto up to the point where the base portion 22 abuts the ram 14. It is seen that an equivalent structure would result if the pins 20 were attached to the frame of the dies 10 and 12 rather than to the frame 13.

According to my upsetting method, a pipe P is heated to forging temperature and installed in the dies 10 and 12. The dies are closed and the pipe is gripped at a remote location. Power is applied to the ram 14 to shove the mandrel 15 into the pipe bore, as shown in Figure 1. The stripper yoke 21 idly moves with the ram and mandrel until its sleeve portion 23 abuts the pipe end, as shown in Figure 2. Thereafter continued movement of the stripper yoke and mandrel forces metal of the pipe into the annular recess which surrounds the section 17 of the mandrel thus forming an internal upset X, as shown in Figure 3.

Next the dies 10 and 12 are opened and the pipe is released so that it is free to move lengthwise. Power is applied to the ram to move the mandrel in the reverse direction. The pipe and stripper guide move freely with the mandrel until the base portion 22 of the latter abuts the frame 13, as shown in Figure 4. Thereafter the pipe and stripper guide are fixed against further movement. Continued movement of the ram and mandrel causes the planishing surface 19 of mandrel head 18 to force the internal upset X outwardly, and thus expands this upset into an external upset Y, as shown in Figure 5. The pipe is then removed from the apparatus and cooled.

From the foregoing description it is seen that my invention affords a simple method and apparatus for externally upsetting pipe in a single operation. The increase in wall thickness at the upset is comparable with that obtained in a single internal upsetting operation. There is no change of tools involved, but instead a single tool forms an internal upset on its instroke, and expands this upset to an external upset on its outstroke.

While I have shown and described only a single embodiment of my invention, it is apparent that modifications may arise. Therefore, I do not Wish to be limited to the disclosure set forth but only by the scope of the appended claims.

I claim:

1. A method of externally upsetting the end portion of Patented Apr. 19, 1960 a metal pipe-comprising heating the end portionofa pipe ain'etalpipe comprising heating the end portion of a pipe tovafiforg'ing"temperature, moving a rigid mandrel into 7 thepip here to "form an intern-a1 upset, and withdrawing the same mandrel to expand the internal upset to an xternalnpset 2-fI.A method pfjexternally upsetting the. endpprtionfpf/ a metal, pipe comprising heating the end pertioniofz a pipe 7 to Dar, forging, temperature, retaining the ,pipefagainstlengthwise movement, moving}, an, annularlvt 'reeessea,

rigid mandrelinto the pipe bore'tofomn aninte a1, upset with a single instrokerof the mandrel, and withdrawing the-mandrel, toexpand the internal :upset, to an external upset, with asingle outstroke of .thesar'ne-mandreL mandrel to expand theiinternal upset to an, external upsetu with asingle outstrokeof the same mandrel.

4. vA method of externally upsetting the, .endpertbntof;

to a forging temperature, elosing dies on the end portion- "of the pipe and retaining the pipe against lengthwise I movement, moving an annularly recessed rigid mandrel into the pipe bore and an abutment against the end face thereof to form an internal upset with a single instroke of the mandrel, opening the dies and releasing the pipe for lengthwise movement, withdrawing the mandrel and abutting the end face of the pipe to expand the internal upset to an eXternabupset-With asing'le outstroke of the same, mandrel.

V R eferences Cited inithe, file of, this patent UNITED STATES PATENTS 1,295,430 Carlson Feb. 23, 1919 1,325,073 Boyd Dec. 16, 1919 1,566,645 Breeze Dec. 22, 1925 2,027,406 Spatta;. Jan. ,14, ,1936 2,053,975 Spatta V e Sept; 1.8,;1936 2,1 46,51 61 Betterton, ,Feb, 7,1939 2,548,702, Chamberlain ;Apr. ,10, 119 52 2,728,135 7 Rockwell .,Dec. 27,1955 

